Not the personal, unable-to-get-out-of-bed depression (which is a relief), but the more broad what-is-the-fucking-point-of-people depression. This tends to be easier to live around, but worse overall, because I can't magic it away with tablets.
It is brought on by reading things like The Economist, or watching things like Darwin's Dangerous Idea on the telly, in which Andrew Marr gives a potted history of humans fucking up the earth in the name of profit, left right and centre, from the Industrial Revolution right up to the present day. You just look at it and wonder what the point is? What is the point of me recycling anything, or not driving my car, or cutting back on air travel? It's too little and it's too late and me and all the people who work even harder than me to actually live some kind of green existence are up against too many forces that just don't give a shit about anything at all other than making money for anything we do to ever make the blindest bit of difference at all.
People say that important movements are built from the grassroots up. Anti-slavery movements, feminism, children's rights, and so forth. But these movements took hundreds of years to develop and very few of them have actually achieved their final ends yet. And environmentalism doesn't have the luxury of time. The world in this picture is not womankind as a whole, or children as a whole, or black people as a whole, but an individual person who is going to die unless someone does something really drastic really right now. But nothing's being done. Or rather, not enough is being done.
On a more focused level, there's all this business about Jade and Dunblane and so on. Normally I get to ignore this kind of thing by not reading the papers, ever, but now here it is, and it's all part of the same cycle, and it makes me, well, very depressed.